Rolling mill



L. IVERSEN ROLLING MILL Ma an, 1941.

Filed May 26, 1934 I u I 4 Sheets-Sheet 1 L. IVERSEN ROLLING MILL May20, 1941.

4 Sheets-Sheet 2 Filed May '26, 1934 May 20, 1941.

L. IVERSEN ROLLING MILL Filed May 26, 1934 4 Sheets-Sheet 4 Patented May20, 1941 ROLLETG MILL Lorenz Iversen, Pittsburgh, Pa, assiznor to MestaMachine Company, Pittsburgh, 1 a corporation of Pennsylvania ApplicationMay 26, 1934, Serial No. 727,701

This invention relates to rolling mills, and particularly to bearingsfor the necks of rolling mill rolls. The invention is hereinparticularly described as applied to the backing rolls of a 4-high stripmill, but it will be understood that this is by way of example only andthat the invention has numerous other applications.

In strip mills of the 4-high type, there are employed relatively smallworking rolls which are supported by backing rolls of larger diameter.The forces to which the rolls are subjected during strip rolling areexceedingly high and in order to reduce the bearing friction to aminimum it has heretofore been common to use roller bearings; Theii-high or cluster type of -mill provides suflicient space for adequatebearings of this type and they have been widely used. Such bearings,however, particularly in the largel sizes, are very expensive, andunless very accurately made, do not function properly. It is essentialin bearings of this type that the inner and outer races be exact both asto diameter and concentricity, and that the rollers be of exact anduniform diameter. The manufacture of such 'bearings entails considerableexpense and of courseconditions existing around strip mills require themost extreme care in the shieldin of the bearings from such deleteriousagents as grit and dirt.

It has heretofore been considered impossible to use bearings of thesliding friction type for mills of the character under discussion.Ordinary brasses" have, of course, been used for many years in varioustypes of mills, but such crosses are not satisfactory for use in modernstrip mills. They wear too rapidly, the coeificientof friction is toohigh, and it is diflicult if not impossible to maintain accuracy ofgauge in the product. It is well recognized that very low coeflicientsof friction can be obtained by high grade oil lubrication, and that ifthe oil film is maintained thin and uniform, a heavy load-carryingcapacity is also obtainable. The difficulty has been that under theconditions existing in rolling mills there has been no possibility ofmeeting such requirements. It must also be borne in mind that accuracyof gauge in the strip is always a paramount consideration andthat' anybearing employed must be such as to insure that the 011 film will be ofsubstantially unvarying thickness insofar as is possible. Otherwise,accuracy of gauge will not be obtained. I i j Another consideration inbearings for rolling mill rolls, constituting a still furtherdiflerentiation from the problem of ordinary machine bearings, arisesout of the fact that the rolls must be periodically removed from themill to have their bodies ground orotherwise dressed. It is importantthat the high quality of the bearing be unaffected by reason of theremoval of a roll for grinding.

I have solved the problem presented and have successfully constructedand used bearings. of the sliding friction or journal type in accordancewith the invention herein described.

In the accompanying drawings illustrating a present preferred form ofthe invention,

Figure l is a side elevation of a 4=high strip mill embodying myimprovements;

Figure 2 isa view of the same mill from the opposite. side;

Figure '3 is a longitudinal section to enlarged scale through one of theimproved bearings;

Figure 4 is a section on the line IV-IV of Figure 3; l Figure 5 is aview to enlarged scale of a portion of Figure 3;

Figure 6 is a longitudinal section on the line VIVI of Figure t;

Figure 7 is a diagram showing the arrangeznent of the journal-engagingsurfaces of the bearing;

Figure 8 is a view to enlarged scale taken on the line VIII-VIII ofFigure 4;

Figure 9 is an enlarged section transverse to the roll axis showinglubricant supply passages, and

Figure 10 is a longitudinal vertical section through the:lournabr-eceiving bearing. shell with the roll neck removed therefrom.

The mill illustrated in Figures 1 and 2 comprises housings carried onshoe plates 3 and having windows 3 in which the mill roll bearings arecarried. The mill has working rolls ii and backing rolls of relativelylarge diameter. The lower backing roll is carried in a chuck l lying atthe bottom of the window and the upper backing roll is mounted in achuck 8, its vertical position being controlled by a screw-down Q. Manyof the details of construction have been omitted from Figures 1 and 2for purposes of clarity in illustration. Figure 2 shows the notched endslb of the working rolls whereby a driving connection is made to them,and also shows the thrust bearings hereinafter described which areprovided for the backing rolls.

' Referring to Figure 3, one of my improved bearings is shown in. detailand in this case the lower backing roll happens tube the one which isillustrated. It will be understood, however,

that the structure is similar for the upper roll.

, It will be further understood that the same hearing structure, exceptfor the thrust bearing structure hereinafter described, is applied ateach end of each backing roll. The backing roll 6, as illustrated inFigure 3, has a neck II, a reduced concentric projecting neck portionl2, and a still further reduced concentric projecting neck portion [3.The portion ll constitutes the shaft portion of the journal bearingwhich carries the rolling load.

The chuck 'l' is made in two halves 1a and lb arranged to be securedtogether by bolts H (see Figures 1 and-2). The chucks I for the lowerroll are carried on rocker plates I5 sothat the chucks for the upperroll are provided with breaker blocks l6 beneath the screw, whichbreaker blocks have interfitting spherical-surfaces, thereby permittinga like tilting action of the upper chucks.

Referring again to Figure 3,the two halves of the chuck I, whenassembled, embrace and rigidly support a'journal-receiving shellindicated generally by the reference character II. The shell is arrangedto stay always with the roll to which it is fitted. When the rollrequires'dressing or when'for any other reason it is replaced, the rollwith its chucks is removed bodily-from themill and the halves of thechucks are then separated. The shells stay with the roll and shouldpreferably never be removed from it, thus insuring'that the coactingsurfaces will not be disturbed. The

sure from the rolling load in the case of the upper roll, and that thelower portion will be under. pressure from such load in the case of 7chucks can tilt bodily as the roll deflects. The

the lower roll.

the lower portion of its bearings.

Figure 7 illustrates thebearing shell in dia- 'f' gram. The portions 2|constitute the bearing surfaces whereas through the portions 22 theshell surface is relieved as shown, so that there i is a small clearancebetween the inner face of the journal shell in the portions 22 and thesurface of theneck. Short inclined portions 22 are provided at thejunctions of the portions 2i and 22. The oil is fed into the clearancespaces provided by the portions 22 and, being entrained by the rotatingneck, is carried'into the bearing portions 2|. The wedge-like transitionportions 23 aid in this and insure that a uniform film of oil will besupplied to the working surfaces.

, Figure 10 shows one of the relieved portions 22 journal-receivingshell l1 carries a positioning pin l8 at the bottom and a like pin I!but of larger diameter at the top. Corresponding re-' cesses areprovided in the chuck halves la and lb as'shown in Figure 3. 'Thisarrangement insures proper positioning of the parts for assembling andprevents the shell being positioned upside down. The pins l8 and I9 holdthe shell against rotation with respect to the chuck, and

chuck and the shell function as a unitary member.

It is important to supply lubricant in such manner that the journal willalways have a proper lubricant supply, and I also make provision forretaining in the bearing aksufiicient shoulders 20 hold the partsagainst relative end-- .wise movement, so that when assembled the inelevation. 1

1;,have found it suflicient for my purposes if oil is merely circulatedthrough the relieved portions 22, and to this end I introduce oilthrough aseries of openings-24 near the bottoms of the clearance spaces22 and take it off through similar openings 25 near the tops of suchclearance spaces. A circulation of oil in direct contact with the rollneck is thereby brought about. Such circulation is in an amountsuflicient to cool the journal and considerably greater than that-required for lubricating the neck. There is no short'circuiting of oil toa degree which precludes adequate lubrication of the working surfacesbecause, as stated, entrainment of the oil by the neck and the provisionof the inclined portions 23, insures that a suflicient quantity forlubrication will be carriedto the working surfaces.

The oil issupplied tothe bearings from a reservoir by means of a pump,and aftercirculating through the bearings the oil is preferablyfiltered, cooled and returned to the reservoir. The reservoir," pump,filter and cooler are well known'expedients and" are not hereinillustrated nor described. Sufilce it to say that the pressure employedis relatively low, for example, ten

' pounds. Pressures of this order are ample to quantity of lubricant toinsure adequate oiling even though the oil supply should fail. I con-.

template supplying oil from a tank by a small pump, but it is importantthat in case of pump failure the bearing shall continue to function.

In point of fact, my bearing does so function,

the only noticeable effect being a slow; rise in temperature whichindicates that the oil supply has failed. The temperature rise is so,slow that v there is .ample time for curing the dificulty withoutendangering the bearingitself.

The bearing loads in rolling are principally vertical. This, of course,holds true only where the rolls are stacked vertically. For example,

' constitute the bearing surfaces. It will be understood thatthe upperportion will be undenpresvisual inspection will show whether or not the"cause circulation of thelubricant through the bearing. Figures 1 and 2illustrate supply pipes 26 and return pipes 21. Pressure gauges arepreferably interposed in the supply lines so that oil is properlycirculating. Oil from the supply pipes 26 is fed to the bearingsthrough-flexible connections 29 coupled to a fitting 30. The oil passesfrom the fitting through a check valve 3! to an. annular passage 32formed by a recess in the bearing shell and having its inner facecovered by a spacer ring 33. The passage 32 communicates withlongitudinally drilled holes 34 (see Figures 4. and .6) leading to theopenings 24. The openings 24 are sumciently small in cross sectioncompared with the cross section of the bore of the holes 36 that asubstantially uniform pressure is obtained throughout the length of thebore 34, and consequently a substantially uniform oil feedlongitudinally of the bearing is obtained. Further assurance that theoil will be properly distributed is obtained by flaring the ends ofthe'openings 24 as indicated at 35.- The oil is thus fed to the recesses22 and flows upwardly therein to the openings-25. It escapes throughthese openings (see Figures 4 and 8)v to longitudinal passages 36,thence to However, between actual rollings' v i the weight of the upperroll may be carried by v check valves 38, to an annular passage 88 (seeFigure from which the oil is taken off through a passage communicatingwith the outlet pipes 21. In case of accidental stoppage of the oilflow, the check valve 3| will seat and a body of oil will thereby bemaintained in the bearing, thus precluding any danger of the bearingbuming out.

is not essential (for a reasonable time at least) to the continuedsupplying of oil to the bearing surface.

It is important to prevent loss of oil from the bearing and it isequally important to seal the bearing against the entrance of water,mill scale,-

and grit. The escape of oil from the bearing during operation isprevented by a dual seal consisting of two closely fitted rings-4| ateach oil which has passed through the bearing and a may be filtered withit for reuse.

The outer sealing rings 4| guard against the entrance of foreign matterfrom the outside and may be supplemented, particularly at the bearingend next to the roll body, by labyrinth water seals .45.

It is equally important that the bearings be protected against theingress of foreign matter when the rolls are taken out, as, for example,for regrinding. The inlet 38 may be capped or plugged but it isimportant that the outlets be likewise closed off and this is morediflicult since, for reasons now apparent, the outlet is preferablyformed in the chuck. The valves 38 and 44 serve to close off the outletswhen the hearing is dis-assembled. To this end they are provided withsprings 46 normally tending to close the valves. The valves are heldopen when the chuck is assembled 'by means of pins 41. As soon as thepressure of the pins 41 is released, as by lifting off the top half ofthe chuck or by lifting the shell out of the lower half, the checkvalves spring shut and stay closed until the bearing is reassembled.

In order to prevent any ingress of foreign matter at the ends of thejournal-receiving shell, provision is made for moving it bodily on theneck and closing off its ends. A nut 48 is threaded on a collar 49secured to the roll neck at the inner end of the reduced portion I2.This nut occupies the position shown in Figure 3 when the parts areassembled for running, but when the roll has been removed from thechucks, the nut 48 may be turned up to engage the end of the bearingshell. Continued rotation of the nut forces a shoulder 58 against theend face of the water lip 5| on the roll body, thereby eifectuallysealing off both endsof the bearing shell.

An important advantage-of my invention from a. practical point of viewis that the bearing shell is smaller than the working roll body, as is'illustrated in Figure 3. The rolls must be removed from the mill fromtime to time for redressing. My improved construction permits of theroll passages?! and, thence through normally open being mounted in aroll grinder or other apparatus and having its surface dressed or turnedwithout the bearing shells in any way hindering the-operation of theroll grinder or other mechanism. At the sametime, the bearing surfacesare so thoroughly protected that there is no I danger of any foreignmaterial, such as dust or It is important to note that in my inventioncirculation of the oil 'eilects cooling but grit, getting into thebearings during the roll dressing operation or during handling of theroll while it is outside the mill.

A hearing of the sort just described will operate witha minimum offriction and with the utmost of satisfaction over long periods of time.

Little or no difliculty will be experienced in keeping it cool or instarting it upunder load. However, additional features of my inventionnow about to be described may be used if it is wished ,to take extraprecautions against such possibilities.

In case the mill should be stopped. under load viding an opening 52communicating with a conduit 53 through which oil is supplied under highpressure. It is to be understood that oil will not ordinarily besupplied through this opening, but if the mill should stand idle for acontinued period of time under load it may be desirable to inject aquantity of oil through the passage under high pressure so as to insurethat no scoring of the journal will result when the mill is started upand before the rotation of the neck has served to carry the oil into thebearing.

It may be desirable, particularly in mills for hot rolling, to provideadditional cooling facilities for the bearings. This may be done ifdesired by using water cooling, I have indicated in Figure 4 one way ofdoing this. The roll is axially bored, as indicated at 54, and water issupplied through the hole. It travels through a radial passage 55 to ahelical passage 56 formed in a sleeve 51 which is shrunk on the neckproper and forms the journal surface. The helical passage extends aroundthe journal for its full length and finally terminates-in a radialopening 58 which leads back to the central bore 54. The central opening54 is plugged between the openings 55 and 58 so as to preventshort-circuiting. The water after going throughone bearingtravels'through the hole 54 to the other end of the roll and travelsthrough similar cooling passages there.

When the roll has been taken out of the mill,

the reduced neck portions l2 serve to support the roll in the roll latheor grinder so that the bearings are not in use at all during theseoperations.

To take care of end thrust there is provided at one end of each roll athrust bearing which is indibut a minimum of axial play. The case hascated in detail in Figure 3. The thrust is met by a collar 59 around theneck portion 13, held in place by an end plate 60 and screws 8|. Thecollar has a flange 62 and thrust rollers 63 carried by cages millhousing by clamps 68 (see Figure 2). The

bracket is free to slide-up and down between the clamps and thehousingin response to the screwdown but with such small clearance as toleave a certain amount of play in the bracket 51 so under load. A radialbearing 69 permits free running of the case 66 on the roll.

A spider I (see Figure 3) is provided to hold the chucks in proper'spaced relation when the parts are assembled ready for placing in themill. This is'a convenient device because the chucks are free to moveendwise with the journal shells on the necks until placed in the housingand thus restrained.

An important advantage of my invention is that it can be used in millswhich have been designed for ordinary roller bearings. The outerdimensions of the chucks can be the same as the chucks for ,rollerbearings. Another important advantage is that by the use of my inventionit is possible to employ rolls with larger necks than would be used onrolls of the same diameter but where rollers bearings are employed. 'I'his per,- mits of making the necks stronger and stifl'er and also givesa greater bearing area and hence a lower unit bearing load.

I have illustrated and described present preferred embodiments of theinvention, but it will be understood that this is by way of illustrationonly and that it may be otherwise embodied or practiced within the scopeof the following claims.

I claim: 1. In a rolling mill, a roll having a neck, a shell embracingthe neck and bodily movable with the roll, and-a sealing ring carried bythe roll gagement therewith.

3. In a rolling mill, 2. roll having a neck, a shell embracing the neck,the shell having a hearing surface extending around a portion only ofthe periphery, the bore being relieved around a portion of thecircumference to provide a space adjacent the bearing surface betweenthe neck and the shell, means for supplying lubricant to a lower portionof such space and for taking oil lubricant at an upper portion thereof,and check means for preventing back flow of lubricant through the inlet.

4:1n a rolling mill, a roll having a neck, a shell embracing the neckand bodily movable with the roll, a chuck arranged to receive andsupport the shell, a passage in the shell to permit flow of lubricant tothe journal, and means for closing off the passage when the shell isseparated from the chuck.

5. In a rolling mill, a roll having a neck, a shell embracing the neckand bodily movable with the roll, a chuck arranged to-receive andsupport the shell, a passage in the shell to permit flow of lubricant tothe journal, a check valve in the passage, and. means on the chuck foropening the check valve when the shell is positioned therein.

6. 'In a rolling mill, a roll having a body and a neck, a shellembracing the neck and bodily removable from the mill with the roll, theshell constituting the stationary member of a neck bearing of thesliding friction type, and a concentric neck portion projecting beyondthe bearing shell and providing an exterior circumferential supportingsurface to permit of mounting the roll, for example, in a roll lathe,for dressing the roll body.

7. In a rolling mill, a roll having a body and a neck, a shell embracingthe neck and bodily removable from the mill with the roll, the shellforming the stationary member of a neck bearing of the sliding frictiontype, a concentric neck portion projecting beyond the bearing shell andproviding a supporting surface to permit of mounting the roll, forexample, in a roll lathe, for dressing the roll body, and means forsealing the ends of the shell during such dressing.

8. In a rolling mill, a roll having a neck, a.

shell embracing the neck, the shell having a bearing surface on theupper portion of its bore, the shell having a relieved portion at theside to provide a recess between the shell and the neck, an inletcommunicating with the recess and adapted for the supply of lubricantthereto, the inlet being adjacent the bottom of the recess, and anoutlet leading from the same recess but a higher level. I

9.'In a rolling mill, a roll having a neck constituting a bearingjournal for the roll, a shell embracing the neck, the shell having acylindrical bearing surface, the cylindrical surface being relieved toprovide a recess between the shell and the neck adjacent such bearingportion, an inlet port adapted for thesupply of lubricant to the recess,an outlet leading from the same recess and means for circulating a floodof oil from the inlet through the recess and to the outlet in amounts inexcess of that required for proper lubrication to remove heat generatedin the bearing.

10. A rolling mill comprising a horizontally disposed mill roll having abody and necks, the necks having surface portions constituting thejournal portions of sliding bearings for the roll, shells encircling andcircumferentially wholly enclosing the necks and making a running fitwith the journals, the roll and the shells constituting a unitassemblage, chucks embracing and supporting the shells, the chucks beingremovable from the shells without disturbing the assemblage of roll andshells, and mill housings having windows for the chucks.

11. A rolling mill comprising a horizontally disposed mill roll having abody and necks, the

necks having surface portions inseparable from, the body andconstituting the journal portions and shells, and mill housings havingwindows' for the chucks.

12. A rolling mill comprising a mill roll having a body and necks, thenecks having surface por-.

tions constituting the journal portions of sliding bearings for theroll, shells encircling and circumferentially wholly enclosing the necksand making a running fit with the journals, the shells being generallycylindrical in external configuration, the roll and the shellsconstituting a unit assemblage, chucks embracing and supporting theshells, the chucks being removable from the shells without disturbingthe assemblage of roll and shells, and mill housings having windows forthe chucks.

13. A rolling mill comprisingsamill roll having a body and necks, thenecks having surface portions constituting the journal portions ofsliding bearings for the roll, shells encircling and cir-'cumferentlally wholly enclosing the necks and making a running fit withthe journals, the shells having outside diameters smaller than the.diameter of the roll body, chucks embracing and supporting the shells,and mill housings having windows for the chucks, the roll with itsshells and chucks being bodily removable from the housings.

14. A rolling mill comprisinga mill roll having a body and necks, thenecks having surface'portions constituting the journal portions ofsliding bearings for the rolls, shells encircling and circumferentiallywholly enclosing the make and making a running fit with the journals,chucks embracing and supporting the shells, means preventing assemblageof the shells in the chucks except in a predetermined orientation, andmill housings having windows for the chucks.

15. A. rolling mill comprising amill roll having abody and necks, thenecks having surface portions constituting the journal portions ofsliding bearings for the roll, shells encircling and circumferentiallywholly enclosing the necks and making a running fit with the journals,the roll and the shells constituting a unit assemblage,

and chucks embracing and supporting the shells, the chucks beingremovable from the shells without disturbing the assemblage of roll andshells, the shells and the chucks having cooperating passages forlubricant.

16. A rolling mill comprising a mill roll having a body and necks, thenecks having surface portions constituting the journal portions ofsliding bearings for the roll, shells encircling and circumferentiallywholly enclosing the necks and making arunning fit with the journals,chucks embracing and supporting the shells, the shells and the chuckshaving cooperating passages for lubricant, and means preventingassemblage of the shells in the chucks except in a predeterminedorientation whereby the cooperating passages register with one another.

17. A rolling mill comprising a mill roll having a body and necks, thenecks having surface portions constituting the journal portions ofsliding bearings for the roll, shells encircling and circumferentiallywholly enclosing the necks and making. a running fit with the journals,chucks embracing and supporting the shells, the shells and the chuckshaving cooperating passages for lubricant, and means for sealing off thepassages in the shells when the same are disassembled from their chucks.

18. In a radial oil film bearing for roll necks, a

bearing shell surrounding the neck of the roll and having a cylindricalbearing surface cooperating with a cylindrical surface on the neck ofthe roll to form an oil film therebetween, oil retaining ringscooperating with surfaces on the roll neck and adapted to confine 011between said bearing surfaces, said rings including a pair of spacedrings at the same end of the bearing surfaces, means for introducing oilto said bearing surfaces, and means communicating with the space betweensaid pair of oil retaining rings and adapted to collect the relativelyclean oil that each shell to seal the end of the shn'rram mgress ofdirt.

, 20. A rolling mill comprising a mill roll having radial oil-filmbearings with lubricant to provide radial oil films between therelatively rotatable members of the bearings of said rolls, and coolingsaid oil films to control the viscosity of said lubricant and maintainoil films of predetermined thickness between said relatively rotatablebearing members. I

22. In rolling-mill practice, mounting the roll necks on radial oil-filmbearings, forming radial oil films between the relatively rotatablebearing members of said rolls to sustain the pressures exerted on saidrolls when in operation, and supplying oil under pressure to said filmsto maintain films of predetermined thickness between the relativelyrotatable members of said bearings.

23. In rolling-mill practice, mounting the roll necks on radial oil-filmbearings, supplying oil under pressure to said bearings to establish oilfilms between the relatively rotatable members of said bearingspreliminarily to starting the rolls in operation, and maintaining radialoil films between said relatively rotatable bearing members while inoperation to sustain the pressures exerted on said rolls uniformlythroughout each rotation thereof.

24. In rolling-mill practice, mounting the roll necks on radial oil-filmbearings, introducing oil under pressure between the relativelyrotatable members of said bearings to establish oil-films therebetweenpreliminarily to starting said rolls in operation, forming radial oilfilms between the relatively rotatable bearing members of, said rolls tosustain the pressures exerted on said rolls when in operation, andthereafter maintaining such a pressure on the oil between saidrelatively rotatable bearing members as to assurethe'main tenance ofpredetermined oil films between said members.

25. In rolling-mill practice, mounting the roll necks on radial oil-filmbearings, supplying said radial bearing with lubricating oil, formingradial oil films between the relatively rotatable bearing members ofsaid rolls to sustain the pressures exerted on said rolls when inoperation uniformly throughout each rotation thereof, and cooling saidoil films to control the viscosity of the oil and maintain predeterminedfilms between said bearing members. I v

26. In rolling-mill practice, mounting the roll necks on radial oil-filmbearings, supplying oil under pressure to saidbearings and formingradial oil films between the relatively rotatable members of said rollsto sustain the pressures exerted on said rolls when in operationuniformly throughout each rotation thereof, and cooling said oil filmsto maintain oil films of proper thickness between said bearing surfaces.

27. In a bearing for roll necks, a sleeve mounted on a roll neck andprovided with'passages for the circulation of water therethrough and abearing shell surrounding said sleeve and having a cylindrical bearingsurface cooperating with the surface of said sleeve to form an oil filmtherebetween, and connections for leading water to and from saidpassages in said sleeve.

28. In a radial oil-film bearing for roll'necks, a bearing shellsurrounding the neck of a roll and having a cylindrical bearing surfacecooperating with a cylindrical surface on the neck to form an oilfilmtherebetween, a chuck surrounding said bearing shell, and means forretaining lubricooperating with a cylindrical surface on the neck of theroll to form an oil film therebetween, spacer rings near each end ofsaid surface, said rings cant in contact with said cylindrical bearingsurfaces including one or more members disposed adjacent to the ends ofbut axially inside of said shell and having oil-retaining contact withsaid cylindrical surface on the neck within the confines of the bearingportion thereof. I

29. In a rolling mill, radial oil film bearings for the necks of. a rolleach of said bearings comprising a bearing shell surrounding the neck ofthe roll and having a cylindrical bearing. surface having an annularrecess open to the roll neck, and a pair of oil seal rings on oppositesides of each spacer ring to exclude dirt and water and a chuck adaptedto receive said shell, a sealing ring mounted on the inner end of thechuck, and a lip projecting from the roll, overhanging the inner end ofthe neck and adapted to cooperate with said sealing ring and to maintainsealing contact therewith notwithstanding relative axial movementtherebetween.

LORENZ IVERSEN. Y

